This invention relates to a machine for producing liquid and semi-liquid food products with a continuous cycle.
In the context of this invention, the term machines for producing liquid and semi-liquid food products refers to machines for producing and processing crushed-ice drinks, sorbets, ice creams, soft ice creams, cream, yoghurt, creams and the like.
Said machines comprise a collection and/or reserve element for the starting food products (such as milk, cream, water and the like) which is connected to a whipping and freezing cylinder.
The collection and/or reserve element may be a container or tank, usually located above the whipping and freezing cylinder, or a “disposable” container made of cardboard or plastic, or of the “bag in box” type.
During machine operation, the starting food product is transferred to the whipping and freezing cylinder which processes the food products to produce the end product (for example, ice cream, yoghurt, creams, crushed-ice drinks).
The whipping and freezing cylinder is normally equipped with a mixer and comprises a shell in which a coolant fluid circulates.
The whipping and freezing cylinder is designed to mix, cool and blend together a plurality of ingredients to form a cream for ice cream, a crushed-ice drink or similar products.
One end of the whipping and freezing cylinder is fitted with a transit opening to which a finished product dispenser is usually connected.
The finished product, pushed by the mixer towards the whipping and freezing cylinder transit opening, is dispensed directly or through the dispenser.
In machines with a continuous cycle the whipping and freezing cylinder operates constantly, that is to say, it is always loaded with basic products which must be transformed into the end product.
For that purpose, each time a portion of finished product is extracted from the whipping and freezing cylinder, an equal volume of starting products must enter the whipping and freezing cylinder to substitute the load extracted.
In continuous cycle machines there are two prior art types of feed to the whipping and freezing cylinder.
A first type, called gravity feed, involves the basic starting products being transferred from the containment tank to the whipping and freezing cylinder substantially by gravity, that is to say, free fall.
A second type of feed, called pump feed, involves using suitable pumps which draw the basic product from the containment tank or from a “disposable” container referred to above and transfer it to the whipping and freezing cylinder.
In particular, pump systems involve the use of a pump which, if the tank is present, is in an upper portion of the tank, whilst if “disposable” containers are used, which are normally positioned inside a cooled compartment, the pump is also usually in the same refrigerated compartment.
The pump is equipped with an intake duct and a delivery duct.
Connected to the intake duct there is a drawing tube extending almost to the bottom of the tank for drawing basic liquid or semi-liquid product. In the case of “disposable” containers, it is fitted with an element able to pierce a container membrane and reach the product inside it to suck it out.
Connected to the delivery duct there is a rigid delivery pipe extending to the bottom of the tank, passing through a hole in it (fitted with seals to prevent liquid product from leaking from the hole) and arriving at an infeed of the whipping and freezing cylinder located below the tank.
In the case of “disposable” containers, said rigid pipe passes through the wall of the refrigerated compartment and arrives at the infeed of the whipping and freezing cylinder which is usually located above the compartment.
The latter type of configuration for continuous cycle machines has poor operating flexibility, since it requires the use of specific pumps for each machine.
For a particular machine for producing liquid or semi-liquid food products, for example a specific machine for producing ice cream, the whipping and freezing cylinder has a food product infeed in a very precise position.
Therefore, the tank used in said machine must have a transit hole for the pump delivery duct which is directly opposite the whipping and freezing cylinder infeed hole. The same disadvantage exists for the refrigerated compartment.
In both cases, a pump must be used which has a delivery duct located in such a way that it is precisely vertically aligned with the hole in the tank, and precisely vertically aligned with the hole in the wall of the refrigerated compartment, to allow the delivery pipe to connect the hole in the tank and the disposable container to the pump delivery duct.
In other words, a specific pump must be used for each type of machine.
This disadvantage is also reflected by high operating costs, since specific spare pumps must be available for each type of machine, making assembly inflexible and expensive.
Moreover, substitution of a faulty pump requires precise assembly with minimum tolerances to guarantee that the delivery pipe can be connected both to the pump delivery duct and to the whipping and freezing cylinder infeed.
This involves lengthy assembly and substitution times.